Police in most states occasionally set up DUI checkpoints (also called sobriety checkpoints or roadside safety checks) to check for drunk or otherwise impaired motorists. Typically, police set up these checkpoints along busy highways during holidays that are notorious for alcohol abuse, such as 4th of July and Memorial Day. Checkpoints usually consist of roadblocks along intersections, where officers stop random vehicles at regular intervals (such as every tenth driver) and check for signs of intoxication.

While DUI or sobriety checkpoints remain controversial and are prohibited in some states, federal law supports their legality.

Learn more about this common law enforcement practice below, and see FindLaw's DUI Stop section for related articles.

The Legal Justification for DUI Checkpoints

Sobriety checkpoints have survived most legal challenges, even in some states where statutes require an officer to have reasonable suspicion of intoxication before initiating a traffic stop. Reasonable suspicion that a motorist may be drunk, and thus subject to a stop, may be established by erratic driving, drifting between lanes, or other suspicious behavior.

But since police at checkpoints stop and question drivers randomly, how are they legal?

The U.S. Supreme Court ruled in 1990 that states had a compelling interest in eradicating drunk driving, and that public safety concerns outweighed any concerns about "intrusion" into drivers' privacy. The challengers in the case had claimed that these checkpoints were unreasonable searches under the 4th Amendment, but the Court found them reasonable under the circumstances. Checkpoints reduce alcohol-related crashes by about 20 percent, according to a U.S. Centers for Disease Control report combining the results of 23 scientific studies.

Sobriety Checkpoints and State Laws

While federal law condones checkpoints for the purpose of maintaining safer roadways, states are free to decide whether or not to use them. DUI checkpoints are not conducted in 12 states because they are either considered illegal by law or state constitution, or the state lacks authority to conduct them:

If you're arrested for impaired driving, it's a good idea to consult with an experienced DUI/DWI lawyer. A skilled attorney who specializes in defending drunk driving charges will evaluate all the evidence, including the legality of a DUI checkpoint, to ensure that your legal rights are protected.

Next Steps

Contact a qualified DUI attorney to make sure your rights are protected.